45 & 9mm chamber

HK45 · April 23, 2006, 10:26 AM

Do the 45ACP and the 9mm Luger cartridge case mouths actually touch the step between the chamber and the bore in my H&K semiautomatic USP Compact pistols, or do the extractors actually set the position of the cartridges at the moment of ignition?

918v · April 23, 2006, 12:14 PM

They actually touch, just barely, because the cases are so short from the factory.

The extractors have alot of room for the case rim to slide forward pursuant to a firing-pin strike.

caz223 · April 23, 2006, 05:22 PM

depends. Measure your brass before and after firing it.
Then measure it again before and after sizing it.
Then you'll get it.
If you're getting good accuracy out of your gun, chances are the brass is headspacing correctly.
If your brass is too short, or worse yet, inconsistant lengths then you'll have accuracy problems from not headspacing the same every time.
Certain brands of brass are more consistant than others.
If you don't sort by headstamp then forget about getting the most accuracy out of your 9mm or .45 auto pistol.
I like WIN brass for consistancy, and if you're going to buy new, then starline is as good/better.

April 23, 2006, 10:26 AM	#1
HK45 Junior Member Join Date: April 22, 2006 Posts: 8	45 & 9mm chamber Do the 45ACP and the 9mm Luger cartridge case mouths actually touch the step between the chamber and the bore in my H&K semiautomatic USP Compact pistols, or do the extractors actually set the position of the cartridges at the moment of ignition?

April 23, 2006, 05:22 PM	#3
caz223 Senior Member Join Date: May 15, 2002 Location: Michigan Posts: 1,429	depends. Measure your brass before and after firing it. Then measure it again before and after sizing it. Then you'll get it. If you're getting good accuracy out of your gun, chances are the brass is headspacing correctly. If your brass is too short, or worse yet, inconsistant lengths then you'll have accuracy problems from not headspacing the same every time. Certain brands of brass are more consistant than others. If you don't sort by headstamp then forget about getting the most accuracy out of your 9mm or .45 auto pistol. I like WIN brass for consistancy, and if you're going to buy new, then starline is as good/better. __________________ I'm not just a gun. I'm YOUR gun. (Hold me.) Last edited by caz223; April 23, 2006 at 08:50 PM.

April 23, 2006, 12:14 PM	#2
918v Junior member Join Date: September 25, 2005 Posts: 1,372	They actually touch, just barely, because the cases are so short from the factory. The extractors have alot of room for the case rim to slide forward pursuant to a firing-pin strike.